(a) Field
The present system and method relate to a quantum dot sheet, and a light unit and a liquid crystal display that includes the quantum dot sheet. More particularly, the present system and method relate to a quantum dot sheet in which phosphor is printed onto an edge surface of the quantum dot sheet, and a light unit and a liquid crystal display that includes the quantum dot sheet.
(b) Description of the Related Art
Unlike a self-emissive display device such as a plasma display panel (PDP) or a field emission display (FED), a liquid crystal display (LCD) is a light-receiving display that cannot form an image from self-light emission and, instead, forms an image with light received from an external source. Thus, the liquid crystal display includes a backlight unit (BLU) that emits light to a display panel.
A backlight unit for a liquid crystal display may use a cold cathode fluorescent lamp (CCFL) as a light source. However, when a CCFL is used as a light source, uniformity of luminance and color purity may deteriorate as the size of the liquid crystal display increases.
Alternatively, a backlight unit may use three-color light emitting diodes (LEDs) to realize high color purity in a high-quality display device. However, compared to a backlight unit that uses a CCFL as a light source, a backlight unit that uses three-color LEDs is very expensive.
One way to overcome such a drawback is to use a white LED that converts light emitted from a mono-color LED chip into white light. However, a white color LED has lower color reproducibility and color purity compared to a three-color LED even though a white color LED has higher economic efficiency. Thus, a method for applying semiconductor nanocrystals to a backlight unit has been proposed to improve color reproducibility and color purity and to assure cost competitiveness.